Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

Abstract

Dislocations are known to be associated with both physical and electrical degradation mechanisms of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). We have observed threading dislocation movement toward the gate-edges in AlGaN/GaN-on-Si HEMT under high reverse bias stressing. Stressed devices have higher threading dislocation densities (i.e. ∼5 × 109/cm2) at the gate-edges, as compared to unstressed devices (i.e. ∼2.5 × 109/cm2). Dislocation movement correlates well with high tensile stress (∼1.6 GPa) at the gate-edges, as seen from inverse piezoelectric calculations and x-ray synchrotron diffraction residual stress measurements. Based on Peierls stress calculation, we believe that threading dislocations move via glide in 〈112¯0〉/{11¯00} and 〈112¯0〉/{11¯01} slip systems. This result illustrates the importance of threading dislocation mobility in controlling the reliability of AlGaN/GaN-on-Si HEMTs.

Impact of carbon impurities on the initial leakage current of AlGaN/GaN high electron mobility transistors

“…However, later studies showed that this is not necessarily the case. Gate-edge degradation is not always accompanied by an increase of the gate-leakage current [5][6][7][8][9] and an increase of the gate-leakage current is not always accompanied by gate-edge degradation [10], [11].…”

Direct observation of recombination-enhanced dislocation glide in heteroepitaxial GaAs on silicon

“…With careful device and contact mask design, we propose that ECCI could even be used to track dislocation evolution in operando. This is a fascinating opportunity to explore the failure mechanisms of semiconductor devices such as GaAs/Si quantum dot lasers [37,38] and GaN [39] and SiC [40] power devices where carrier recombination or electric field-induced dislocation motion is suspected or has been observed postdegradation.…”

On-state reliability study of AlGaN/GaN high electron mobility transistor on silicon

“…This phenomenon correlates well with the formation of physical defects such as pits [75], cracks [13] and grooves [14] via electro-chemical oxidation process [16]. The formation of these defects is dependent on various factors such as threading dislocation [75,76], applied bias [14], temperature [77] and stressing duration [78].…”

“…For OFF-state reliability, it was found that the physical defect formation depends on various factors such as applied voltage [81], threading dislocation [75,76], environment [15], and stressing duration [78]. Several mechanisms have been proposed to explain the OFF-state degradation such as inverse piezoelectric [13], electro-chemical oxidation [16] and percolation path-induced degradation [17].…”

“…In order to do this, the effect of other factors that may cause device degradation i.e. temperature [77], threading dislocation [75,76] and applied bias [81,114,153] have to be minimized. The first part of the chapter discusses about how to decouple the effect of current density from temperature and electric field during ON-state degradation.…”